To prevent a subject vehicle from coming close to another vehicle at an intersection, a technique has been conventionally known which includes detecting the position of the subject vehicle, acquiring lane information of a road on which the subject vehicle travels from map information on the basis of the detected position of the subject vehicle, specifying a lane in which the subject vehicle travels and a traveling direction of the subject vehicle, and transmitting the specified information of the lane and the traveling direction to another vehicle (see Japanese Patent Application Publication No. 2010-259021A).
When specifying the lane in which the subject vehicle travels, the position of the subject vehicle has to be detected with a high degree of accuracy. In the conventional technique, however, the sensor for detecting the position of a vehicle with a high degree of accuracy is expensive, which may cause an increased cost for producing vehicles.
A problem to be solved by the present invention is to provide a travel control method that allows information on lane boundary lines to be appropriately output.